The present invention relates to shim elements or spacers, particularly to such elements designed for use between structural steel beams and hanger assemblies which have aligned pairs of bolt-receiving passages or holes through which bolts are passed and fastened for purposes of uniting the beams, girders or plates to each other or to other structural members.
It is common practice in the structural steel building trade to insert shim elements between steel beams and hangers or suspended units, before such elements are bolted together, in order to level the continuous member of the hung unit since some small difference is generally encountered even though the steel parts are produced with the best possible precision. In many instances, it is necessary to insert a plurality of superposed shim elements. For the best results, the shim elements should be U-shaped and comprise spaced legs and a central recess. Such shim elements are slipped between the beams and hangers with one leg on each side of each bolt so that each bolt is received within a shim recess. Thus, when the bolts are tightened the shim support evenly surrounds each bolt.
Structural steel bolt holes are conventionally precision-spaced from each other by a distance of 21/2 inches, 3 inches or 31/2 inches, depending upon the size of the steel beams or girders being used. In order to be used in side-by-side close relation, without overlapping, it has been necessary to stock a plurality of different-sized shim elements, each element having legs of the same width and the width of said legs increasing with the size of the elements to accommodate bolts spaced by different distances. This has been expensive and burdensome.
It is not acceptable to use shims having narrow legs for all applications because, while such shims fit in all applications, they are spaced from each other in side-by-side relation by too great a distance when the bolts are spaced by more than the minimum spacing, i.e., by more than 21/2 inches. While it is not necessary that the shims contact each other, any spacing therebetween must not exceed about 1/4 inch in order to satisfy bearing requirements and structural specifications.